Contents

Importance

The yellow-bellied sapsucker, Sphyrapicus varius L., pecks small holes in tree bark, causing injuries that are often mistaken for insect borers—hence its coverage in this paper. This pest is found over most of the United States and southern Canada, but its damage is best known in the Eastern United States. It attacks pecan and hickory as well as over 250 other trees and shrubs (Beal and McAtee 1922). As portions of the bark and cambium are removed by numerous pecked holes, the vitality of the tree is lowered. When the injury is extensive, individual branches or the entire tree may be completely ringed or girdled and killed. Sapsucker pecking disfigures ornamental trees and gives rise to holes, to sap spots, and subsequently to gnarled bark deformities that ruin the aesthetic appearance of the trees. Disease and wood-boring insects often become established at sapsucker wounds. The greatest damage done by sapsucker, however, is to cause defects in the wood of trees cut for lumber, veneer, and handle stock. Economic losses to the lumber industry in hickory alone have been estimated at 1.2 million dollars annually (Dale and Krefting 1966).

Description

The yellow-bellied sapsucker is a member of the woodpecker family (Picidae) and resembles the woodpeckers in appearance (fig. 26A). However, its habits are detrimental as opposed to the generally beneficial habits of woodpeckers. The identifying field markings of adult birds are a black crescent on the breast, pale yellow belly, longitudinal white stripe on the mostly black wings, and crimson red crown (Peterson 1947, Ostry and Nicholls 1976). Although it most closely resembles the hairy and downy woodpeckers and is between the two in size, it is the only woodpecker with a red forehead in combination with a black patch on the breast. In addition, the male has a crimson chin and throat that distinguish him from the female whose chin and throat are white.

Evidence of Infestation

The yellow-bellied sapsucker pecks a series of small holes about 5 mm in diameter in the bark (Beal and McAtee 1952). Generally, the holes are made in horizontal rings (full or partial) around the trunk or branches. The holes extend through the bark to the cambium, sometimes penetrating the sapwood to a depth of 3 mm. Occasionally the holes in a series are gradually enlarged until they girdle or partially girdle the stem. Dissections of trees that have suffered from repeated yearly attacks reveal characteristic symptoms of previous damage by sapsuckers. The evidence consists of uniformly spaced peck-marks surrounded by dark vertical stains, often with small pockets of ingrown bark and decay. These defects degrade the lumber sawn from damaged trees (fig. 26C). Attacks may be seen at any point on the trunk and branches but are perhaps most common on the bole area just below the lower branches. Small trees are particularly susceptible to attack.

Biology

Although the yellow-bellied sapsucker is a member of the woodpecker family, it has a short brush tongue in contrast to that of true woodpeckers, which have long tongues equipped with barbed tips for preying upon wood-boring grubs. The sapsucker's staple diet is the living cambium layer, inner bark, and sap that flows from the pecked wounds (Dale and Krefting 1966). After settling in a locality, each bird pecks many trees but then selects a few trees for most of its feeding. Pecked holes are revisited several times daily to drink sap oozing from the wounds and to eat small insects attracted to the sap. On favored trees, holes are often enlarged as the sapsucker feeds on the cambium to freshen the wound and to stimulate sap flow. The yellow-bellied sapsucker is a migratory bird that spends its summers and nests primarily in the Northern States and southern Canada (Peterson 1947). In the fall it migrates southward, sometimes as far as the Gulf Coast.

Control

Control is difficult, but several remedies have been used with some success on high-value trees (Ostry and Nicholls 1976, Beal and McAtee 1922). Trunks of individual trees may be wrapped with burlap or some other material to prevent attacks. Painting damaged trees with tree-wound paint will sometimes discourage the birds. Commercially available repellents have been used successfully in repelling sapsuckers. Spraying the trunk periodically with a soap solution has also helped to disourage attacks. Often only a single bird is responsible for damage to a shade or ornamental tree; thus, if it can be discouraged or eliminated, the problem is solved.